Which sentence is the CLEAREST?

"At the age of twelve, my parents sent me to boarding school." and "My parents, at the age of twelve, sent me to boarding school" make it sound like the parents were age twelve, when in fact it was the narrator. "At the age of twelve, I sent my parents to boarding school." makes it sound like the parents were sent to boarding school. Only "When I was twelve, my parents sent me to boarding school." has the clearest, most logical meaning.